1. Field of the Invention
The present invention generally concerns downhole valves that are particularly useful in petroleum production wells for accomplishing a wide variety of control functions. More particularly, the present invention concerns a downhole valve that is operable without necessitating the presence of control cables, conductors in the well, or mechanical manipulators, and which may be made responsive to predetermined instructions to perform predetermined well control functions.
2. Description of the Related Art
Historically, one of the limiting factors of downhole valves has been the need to power and/or operate such valves from the surface necessitating the presence of control cables, conductors in the well, or mechanical manipulators. An example of a tool string that may be deployed in a well, including a typical downhole valve, is described in U.S. Pat. No. 5,350,018, which is incorporated herein by reference. The tool string of the ""018 patent communicates with the surface by means of an electrical conductor cable deployed in the coiled tubing by which the tool string is run into the well. Certain downhole valves are designed to be operated using push/pull techniques requiring highly skilled and experienced operators. Such techniques often produce inconsistent results. Hence, a downhole valve that is powered and operated without the use of a conductor from the surface or mechanical manipulation is highly desirable.
The present invention provides a downhole valve system that is operable from the surface without necessitating that the well or downhole tool conveyance mechanism of the valve be equipped with electrical power and control cables extending from the surface to the downhole valve, and without the use of complex and inherently unreliable mechanical shifting or push/pull techniques requiring downhole movement controlled remotely from the surface.
The valve of the present invention, identified as an indexing valve, directs internal fluid flow through one or more ports. The valve utilizes a motor-driven rotary indexer to actuate sealing elements to open and close ports in the valve body. The valve motor is powered by a downhole battery. The downhole battery may be mounted in a side pocket mandrel and may be changed by means of a kick-over tool.
The specification also describes how a wireless telemetry system may be used to control the downhole valve of the present invention remotely from the surface. The downhole valve may be controlled by any or all of multiple types of shaped internal telemetry devices, (for example, balls, darts, or objects of other suitable geometry), sent or dropped downhole, carrying information to a downhole sensor to cause the valve to actuate. These shaped internal telemetry devices, regardless of their geometry, may be classified as Type I, II, or III, or combinations of Types I, II, and III.
A Type I internal telemetry device has an identification number or other designation corresponding to a predetermined event. Once a downhole sensor receives or detects the device identification number or code, a pre-programmed computer will perform a series of logical analyses and then actuate the downhole valve to a predetermined position.
A Type II internal telemetry device has a reprogrammable memory that may be programmed at the surface with an instruction set which, when detected by a downhole sensor, causes the downhole valve to actuate according to the instruction set. The downhole device may also write information to the Type II tag for return to surface.
A Type III internal telemetry device has one or more embedded sensors. This type of device can combine two or more commands together. For example, a Type III device may have a water sensor embedded therein. After landing downhole, if water is detected, the Type III device issues a command corresponding to a downhole actuation event, for example closing of the downhole valve.